Core clamp



CORE CLAMP Eed Dec. 2'?, 194B H. R'. KORTE July 20, 1943.

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H erm am 1Q. Korte by )Va/y ,JMA/M4 His Attorney.

corners being furthermore suitably rounded not only for facilitating thestamping operation but also for the purpose of improving the stressdistribution as will be more fully explained hereinafter. After thestamping operation is completed, the edges of the channel sides may betrimmed, if necessary, in order that the edges will lie in asubstantially common plane throughout the channel sides. {Ihe twoclamping members are placed against the opposite sides of the corestructure with the edges of the channel sides against the fiat orlongitudinal surface of the laminations, it being understood that thewidth of the channel of the clamp members is somewhat less than thewidth of the outer core legs and yokes of the core structure. The twoclamp members are forced `together by means of a pair of bolts 35 and 36which extend through cooperating holes pro-` vided in the yokes of the Elaminations of the reactor units Il and I2. The cooperating openings inthe clamp members being in substantial registry with the holes orapertures in the yokes are elongated in the direction of the core axisin order to permit adjustment of the non-magnetic gaps in a manner to bepresently described. Suitable washers 31 are provided between the headand nut of the bolt and the clamping members. Thus, each of the framemembers has a generally ring-like shape with straight sides connected bywholly rounded corners and has a substantially uniform channel shapecross section at all points around its periphery so that the coremembers may be clamped tightly tgether.

Because of the channel cross sectional shape of the clamp members, theywill be Very rigid due to the fact that the channel sides thereof extendedgewise with respect to the core surfaces. So great is their rigiditythat only two bolts are required, as shown, for securely clampingtogether a core structure of the type herein described comprising threeseparate lamination stacks. By providing rounded corners for the clampmembers there is no`such concentration of stress as might cause bendingof the clamp members at these points, and as a result, tightening of thebolts at the opposite ends of the assembly will exert sufficientcompressive force between the clamp members throughout their length soas to adequately clamp together the laminations of the intermediatetransformer unit as well as those of the reactor units.

After the unit has been assembled, the leads of the various windings maybe connected to indicating instruments of the testing apparatus (notshown), and the operational characteristics of the device may beadjusted, if necessary,

by slightly varying the spacing of the non-magnetic gaps through the useof any suitable means. It will be readily understood by those skilled inthe art that even though a non-magnetic spacer 25 is selected of such apredetermined thickness which should give the required gap spacing,further adjustment of the gap may be necessary depending upon the degreeof accuracy required in the finished product. Such adjustment may beaccomplished by simply tappin'g the appropriate end of the device with asmall mallet, variously comprising the fibrous spacer 24 or25 until theexact desired indication is obtained on the test instruments., By reasonof the slightly elongated holes provided in the core clamps, the coresof the two reactance units may be shifted somewhat for effecting theadjustment of the non-magnetic gaps relative to the transformer core.Since the bolts 35 and 36 extend laterally or at right angles withrespect to the lamination stacks, there will be no tendency on the partof these bolts to alter'the nonmagnetic gap spacing once it has beenadjusted. The contact friction between the edges of the clamp membersand the laminations will hold the cores rmly and maintain the gap asadjusted throughout the remainder of the assembly operation.

The transformer device may now be mounted within an enclosing housing39, as shown in Fig.-

3, which may then be filled with a suitable insulating compoundindicated at 40, substantially lling the housing after which the cover4l may be applied. l

It will be apparent that the clamping arrangement of this invention isextremely simple and of low manufacturing cost, and yet at the same timemay be adapted for clamping relatively complicated core structures, suchas that shown. The clamping device serves not only for fasteningtogether the laminations of a number of individual core stacks, butbecause of the great rigidity of the clamp members, it may also beutilized for securing the plurality of core stacks relative to eachother in a predetermined spaced relation.

Having described my invention in what I consider to represent apreferred embodiment thereof, I desire to have it 'understood that thespecic structure shown is merely illustrative and that the invention maybe carried out by other means. y

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

l. A clamp for a stack of magnetic core laminations having outer corelegs and yokes comprising a pair of stamped sheet metal frame members,each of said members having a generally rectangularly ring-like shapewith straight sides connected by wholly rounded corners and conformingto the contour of the outer legs and yokes, each of said members havingsubstantially uniform channel shaped cross section of less width thanthat of the legs and yokes at all points around its periphery, the edgesof the channel sides being continuous and terminating apparatus having asubstantially rectangular laminated magnetic core with outer legs andyokes, a pair of clamping members for said core each comprising astamped substantially rectangularly ring-like shaped sheet metal framewith straight sides connected by rounded corners and conforming to thecontour of the outer legs and yokes, each of said frames having asubstantially uniform channel shaped cross section at all points aroundits periphery, each of said frames around its periphery having a widthless than the width of the outer legs and yokes and` contlnuous edgesterminating in a common planev so that the channel edges of saidframes-will en-` gage said outer legs and yokes of said substantiallyrectangular core, and means for clamping shaped sheet metal frame withstraight sides y connected by wholly rounded corners, said framesincluding said corners having a substantially uniform channel shapedcross section of less width than that of the legs and yokes at allpoints around its periphery with continuous edges terminating in acommon plane, and clamping means for forcing said frames againstopposite surfaces of said core with the channels of said frames facingsaid core.

HERMAN R. KORTE.

